The present invention relates to image processing technology suitable for game machines which present images in three-dimensional virtual space. More particularly, the present invention provides image processing which can pull a player deeply into a roll-playing game by realistically displaying the images displayed therein and imparting natural image changes.
In television game machines, roll-playing games that employ three-dimensional image processing technology are very popular because of the beauty of the imagery and the depth of the story provided. Most roll-playing games employ computer graphics technology in configurations wherein it is possible to display many displayed entities (hereinafter called xe2x80x9cobjectsxe2x80x9d) in three-dimensional virtual space. These objects include, in addition to those which simulate such real-world forms as terrain, plants, animals, and buildings, those (hereinafter called xe2x80x9ccharactersxe2x80x9d) which model the hero of the roll-playing game and other persons who appear in the game. In this game machine, the character corresponding to the hero is configured so that it can move in virtual space in response to manipulations of an input device by a player. This game machine, moreover, develops the game story while concomitantly moving the point of view for displaying images in virtual space so as to follow the movement of the hero character, moving the virtual space together with the characters and image-displaying objects one after another as they appear.
In a conventional roll-playing game, due to the necessity of clearly presenting the way the virtual space looks to the player, innovative measures have been implemented in the object display methods. In cases where characters enter and leave an object simulating a building, for example, either the building is made partially transparent or the object is displayed without a roof, to facilitate viewing the movements of the characters that have entered the building.
If the object simulates a tree, the texture of the entire tree is represented on flat polygons, compositions are made wherein polygons mapped with texture to represent leaves are inserted in a cruciform in the middle of the trunk, or the tree is represented by ball-shaped objects, thus mapping texture data to make [the object] look like a tree on the polygons.
In some cases realism is further enhanced by displaying shadows that follow the movement of the characters.
It is desirable, however, to design a roll-playing game so that the player becomes totally immersed in the image world presented by the game machine and becomes emotionally identified with the hero as the game progresses. When conventional roll-playing games are evaluated from this perspective, a number of difficulties become evident.
For example, in game machines where a portion of a building is removed when a character enters therein, the player engaged in the game is made to feel a sense of discord because of the unnaturalness which ensues when suddenly a portion of the building disappears or the screen changes to a display of a house interior or the like. If the building is displayed from the beginning with no roof, on the other hand, this presents anything but a realistic image, so the sense of realism cannot be enhanced.
In a roll-playing game, moreover, where a character goes is determined by player manipulations, so there are cases where an extreme approach is made to an object. If the object approached by the character is one that simulates a tree with a conventional method, however, the shapes of microscopic objects are far removed from the shape of a real tree, resulting in an image that is altogether unnatural.
Having said that, however, to try therefore to represent every individual leaf with a polygon is something that can hardly be handled by a game machine that is severely restricted in terms of machine performance and processing time.
With the conventional method for displaying shadows, moreover, a black disk-shaped object is deployed at the feet of the character and both objects are moved together to display the shadow. In cases where the terrain is uneven, however, a method involving a great computation load has been employed wherein the shadow object is floated in conjunction with the terrain in order to prevent the shadow object from sinking into the ground. The only way to lighten that computation load has been to ignore the fact when a shadow sinks into the ground. Hence it has been very difficult to display natural shadows.
In view of the difficulties described in the foregoing, a first object of the present invention is to provide image display that makes natural display transitions possible when a character enters or leaves an object, without losing the sense of realism.
A second object of the present invention is to provide image display wherewith, when displaying objects like trees, the shapes of the trees and the like can be displayed with a natural sense of texture even when those objects are displayed large.
A third object of the present invention is to provide image display that can display natural shadows that do not impair the sense of realism, without increasing the computation load.
A fourth object of the present invention is to provide a game machine wherewith the image processing of the present invention is possible.
A fifth object of the present invention is to provide a recording medium capable of providing a program wherewith the image processing of the present invention is possible.
An invention for realizing the first object stated above is an image processing unit or method thereof configured so that it is possible to display one or more objects deployed in virtual space and a character established that can move relative to the object or objects, configured so that, when the character meets a certain condition relative to the object, of the display elements configuring the object deployed in an area related to the movement of the character, the display density of at least some specific display elements can be gradually altered.
By xe2x80x9cobjectxe2x80x9d is meant a displayed entity, which here refers to the relationship between an object representing a character, for example, and an object representing a building that the character enters or leaves. However, this can be applied to all cases where one object enters into another object. The xe2x80x9ccertain conditionxe2x80x9d is, for example, that the character mentioned above enters or leaves the interior of the object mentioned above. This may be determined when the distance between two objects reaches a certain value, or indirectly by condition established by the progress of the game such as that xe2x80x9ca door openedxe2x80x9d or xe2x80x9ca window opened.xe2x80x9dBy xe2x80x9crelated areaxe2x80x9d is meant something like an area that should be established so that an object which has entered an interior is made visible by altering the display density, or an area wherein it is necessary to display an interior during the progress of the game. In the case of a building, for example, this would correspond to a self-contained area such as the first floor or the second floor, etc. The xe2x80x9cat least some specific display elementsxe2x80x9d can be set discretionarily. For example, these could be display elements, of the display elements configuring the object mentioned earlier, positioned on the side of the point of view established in the virtual space for the purpose of generating display images. Because this is xe2x80x9cat least some,xe2x80x9d the transparency of the entire building may be adjusted or the transparency of a specific portion thereof may be adjusted. As to the specific method of alteration, the display density for the specific display elements mentioned above would be gradually diminished when the character mentioned above enters the object mentioned above, and increased when the character leaves.
It is here desirable that a thickness be established beforehand for the partitioning members configuring the object. Thereupon, prescribed texture data are mapped to the cross-section of the partitioning members displayed by display elements other than the specific display elements mentioned earlier.
An invention for realizing the second object stated above is an image processing unit or method thereof configured so that objects deployed in three-dimensional virtual space can be displayed, being configured so that an image simulating a tree-shaped form can be displayed by deploying flat display elements, whereto prescribed texture data have been mapped, radially about a prescribed center axis so as to subtend a certain angle or angles with that center axis to configure an object, and deploying one or more such objects in the virtual space stacked up in the vertical dimension (vertical dimension established in the virtual space).
The xe2x80x9ccenter axisxe2x80x9d here refers to that portion corresponding to the trunk. In terms of the overall deployment, a cone or umbrella shape is effected. There is also no necessity that the display elements incline outwardly in the same manner. They may open upward in the coordinates of the virtual space, and the angles of opening may be made random. The term xe2x80x9ctree-shaped formxe2x80x9d refers, in addition to trees, to forms having indistinct shapes occurring in the natural world such as flames, smoke, and clouds, for example, and can be applied to all kinds of things.
Here, of the plurality of objects mentioned in the foregoing, those objects which cover the uppermost end are configured in roughly in umbrella shape. As to objects at lower levels, however, portions near the center axis cannot be seen, wherefore it is not absolutely necessary that texture data be mapped in close proximity to the center axis.
The configuration is also made so that adjustments are made so that display elements whereto the same texture data are mapped are not stacked on top of one another between a plurality of the objects mentioned earlier which are adjacent. In order to prevent display elements from being stacked on each other, the orientation of each object (angle of object about center axis) can be changed or the order of the display elements making up an object can be changed, object by object. Alternatively, settings may be made so that the plane of each display element protrudes out beyond the outer circumference. Or the planes of the display elements configuring the aforementioned objects may be deployed at different levels so that they do not contact each other. Or the display element planes may be arranged so that they form a delta-shaped zigzag pattern.
Another invention for realizing the second object stated above is an image processing unit or method thereof configured so that objects deployed in three-dimensional virtual space can be displayed, wherein flat display elements, whereto prescribed texture data have been mapped, are deployed in a plurality within a prescribed space area to configure one object, configured such that the directions in which the faces of the plurality of those display elements are oriented can be controlled to correspond with the point of view from which the virtual space is observed.
The xe2x80x9cobjectxe2x80x9d referred to here may suitably be a tree or other entity in the natural world having a complex shape. When the xe2x80x9cobjectxe2x80x9d is a tree, the xe2x80x9cdisplay elementsxe2x80x9d may suitably be a cluster of leaves configuring the tree. The main idea is to divide one tree into blocks that comprise a plurality of display elements, and effect control so that the display elements more or less face in the direction of the point of view.
One conceivable method of directional control is to establish one representative point vector for one of the objects noted above in correspondence with the point of view mentioned above, and then directionally control the display elements noted above so that a plurality of those display elements face in the direction of that representative point vector.
Another conceivable method of directional control is to directionally control the display elements noted above so that each of the normal lines in the plurality of the display elements noted above are oriented in the direction of the point of view noted above.
For example, the configuration may be made such that weighting coefficients are set to the apexes of the display elements, and the density of the texture mapped to those display elements can be linearly interpolated by those weighting coefficients between the apexes, and the configuration be made such that, by modifying the weighting coefficients so that they are made to correspond with the deployment of the object in virtual space, the density of the texture of the display elements configuring that object can be controlled.
An invention for realizing the third object stated above is an image processing unit or method thereof configured so that it is possible to display objects deployed in virtual space and the shadows of those objects, configured so that an object can be generated for displaying the shadow between the aforesaid object and the point of view for displaying the image.
The configuration is made here so that the relative positions of the object and the shadow object therefor as seen from the point of view can be altered according to the height of the object above a reference plane deployed in the virtual space. The configuration is made, for example, so that the shadow can be moved up and down on the screen in correspondence with that height.
An invention for realizing the third object stated above is an image processing unit or method thereof configured so that an object deployed in virtual space and a shadow therefor can be displayed, being configured so that a light source for shining an illuminating light for the purpose of displaying the shadow can be established in an area of a reference plane established in the virtual space wherein the shadow of the object is to be displayed. For example, a black light could be deployed at a position corresponding to the sun in the virtual space. The shining position is below the legs of the object, but the shining position may be changed according to the angle of the sun and the height of the object above the reference plane.
An invention for realizing the fourth object stated above is a game machine characterized in that it comprises an image processing unit of the present invention.
An invention for realizing trio fifth object stated above is a recording medium that is machine-readable and whereon are recorded program data for executing an image processing method of the present invention on a computer.
By recording medium is meant some thing whereon information (primarily digital data, programs) is recorded by some physical means, which is capable of causing a computer, dedicated processor, or other processing apparatus to perform prescribed functions. In other words, this recording medium may be anything which will download a program to a computer by some means and cause the prescribed functions to be executed. Such media include flexible disks, hard disks, magnetic tape, optical magnetic disks, CDs, CD-ROMs, CD-Rs, DVD-RAMs, DVD-ROMs, DVD-Rs, PDs, MDs, DCCs, ROM cartridges, RAM memory cartridges having battery backup, flash memory cartridges, and non-volatile RAM cartridges, etc.
Also included are cases where data transfer is received from a host computer via a wire or wireless communications line (public line, dedicated data line, satellite link, etc.). The so-called Internet is also included in the recording media referred to here.